[tip: perf/kprobes] s390: kprobes: Use generic kretprobe trampoline handler

tip-bot2 for Masami Hiramatsu
2020-09-14T17:21:56Z

The following commit has been merged into the perf/kprobes branch of tip:

Commit-ID: 26a24a6b43d51c6fc70bef9b9016d81e4cf75e6e
Gitweb: https://git.kernel.org/tip/26a24a6b43d51c6fc70bef9b9016d81e4cf75e6e
Author: Masami Hiramatsu <mhiramat@kernel.org>
AuthorDate: Sat, 29 Aug 2020 22:02:04 +09:00
Committer: Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 08 Sep 2020 11:52:34 +02:00

s390: kprobes: Use generic kretprobe trampoline handler

Use the generic kretprobe trampoline handler. Don't use
framepointer verification.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/159870612453.1229682.15950927742606892302.stgit@devnote2
---
arch/s390/kernel/kprobes.c | 79 +-------------------------------------
1 file changed, 2 insertions(+), 77 deletions(-)

diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c
index d2a71d8..fc30e79 100644
--- a/arch/s390/kernel/kprobes.c
+++ b/arch/s390/kernel/kprobes.c
@@ -228,6 +228,7 @@ NOKPROBE_SYMBOL(pop_kprobe);
void arch_prepare_kretprobe(struct kretprobe_instance *ri, struct pt_regs *regs)
{
ri->ret_addr = (kprobe_opcode_t *) regs->gprs[14];
+ ri->fp = NULL;

/* Replace the return addr with trampoline addr */
regs->gprs[14] = (unsigned long) &kretprobe_trampoline;
@@ -331,83 +332,7 @@ static void __used kretprobe_trampoline_holder(void)
*/
static int trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
{
- struct kretprobe_instance *ri;
- struct hlist_head *head, empty_rp;
- struct hlist_node *tmp;
- unsigned long flags, orig_ret_address;
- unsigned long trampoline_address;
- kprobe_opcode_t *correct_ret_addr;
-
- INIT_HLIST_HEAD(&empty_rp);
- kretprobe_hash_lock(current, &head, &flags);
-
- /*
- * It is possible to have multiple instances associated with a given
- * task either because an multiple functions in the call path
- * have a return probe installed on them, and/or more than one return
- * return probe was registered for a target function.
- *
- * We can handle this because:
- * - instances are always inserted at the head of the list
- * - when multiple return probes are registered for the same
- * function, the first instance's ret_addr will point to the
- * real return address, and all the rest will point to
- * kretprobe_trampoline
- */
- ri = NULL;
- orig_ret_address = 0;
- correct_ret_addr = NULL;
- trampoline_address = (unsigned long) &kretprobe_trampoline;
- hlist_for_each_entry_safe(ri, tmp, head, hlist) {
- if (ri->task != current)
- /* another task is sharing our hash bucket */
- continue;
-
- orig_ret_address = (unsigned long) ri->ret_addr;
-
- if (orig_ret_address != trampoline_address)
- /*
- * This is the real return address. Any other
- * instances associated with this task are for
- * other calls deeper on the call stack
- */
- break;
- }
-
- kretprobe_assert(ri, orig_ret_address, trampoline_address);
-
- correct_ret_addr = ri->ret_addr;
- hlist_for_each_entry_safe(ri, tmp, head, hlist) {
- if (ri->task != current)
- /* another task is sharing our hash bucket */
- continue;
-
- orig_ret_address = (unsigned long) ri->ret_addr;
-
- if (ri->rp && ri->rp->handler) {
- ri->ret_addr = correct_ret_addr;
- ri->rp->handler(ri, regs);
- }
-
- recycle_rp_inst(ri, &empty_rp);
-
- if (orig_ret_address != trampoline_address)
- /*
- * This is the real return address. Any other
- * instances associated with this task are for
- * other calls deeper on the call stack
- */
- break;
- }
-
- regs->psw.addr = orig_ret_address;
-
- kretprobe_hash_unlock(current, &flags);
-
- hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
- hlist_del(&ri->hlist);
- kfree(ri);
- }
+ regs->psw.addr = __kretprobe_trampoline_handler(regs, &kretprobe_trampoline, NULL);
/*
* By returning a non-zero value, we are telling
* kprobe_handler() that we don't want the post_handler